This invention relates to a targeting device for inserting a fastener into the distal end of a femoral nail.
Intramedullary nailing has become one of the most effective methods for stabilizing orthopedic shaft fractures. Designs that interlock bone and nail have expanded the indications for Intramedullary Nailing (IM) considerably.
These interlocking nail designs, while generally successful, are associated with some difficulties, such as an inability to localize the distal locking holes and missed locking, that result in prolonged operating and fluoroscopy time. In addition, since no reliable distal targeting device has been developed, most surgeons are exposed to considerable radiation during distal screw insertion.
The problem of properly inserting the distal locking screws from outside the limb of the patient into corresponding screw holes in the nail is a challenging one. The proper positioning of such locking screws or pins is typically the most time-consuming and difficult portion of the overall nail implantation procedure.
A number of different approaches have been taken in attempting to find an effective, safe, simple, and rapid method. These include U.S. Pat. No. 5,772,594 issued Jun. 30, 1998, to Earl F. Barrick for "Fluoroscopic Image Guided Orthopaedic Surgery System with Intraoperative Registration"; U.S. Pat. No. 5,540,691 issued Jul. 30, 1996 to John A. Elstrom and Peter Elstrom for "Optical Distal Targeting method for an Intramedullary Nail"; U.S. Pat. No. 5,013,317 issued May 7, 1991 to J. Dean Cole and A. Glenn Durham for "Medical Drill Assembly Transparent to X-rays and Targeting Drill Bit"; U.S. Pat. No. 4,976,713 issued Dec. 11, 1990 to Joel Landanger and Jean P. Michel for "Aiming Device to Position at Least One Fixing Component of the Centromedullar Nail Type, Through an Implant"; U.S. Pat. No. 4,803,976 issued Feb. 14, 1989 to Robert Frigg et al. for "Sighting Instrument"; U.S. Pat. No. 4,667,664 issued May 26, 1987 to Harold S. Taylor and John C. Taylor for "Blind Hole Targeting Device for Orthopedic Surgery"; and U.S. Pat. No. 4,418,422 issued Nov. 29, 1983 to Karl M. Richter et al. for "Aiming Device for Setting Nails in Bones".
Typically, a C-arm x-ray provides an image for the surgeon to view the locking holes in the nail. It is necessary to precisely align the axis of the targeting device with the axis of the locking holes after the radiation axis of the x-ray has been aligned with the locking holes. Usually prior art viewing devices employ a carriage mounted on a mounting plate to move the targeting device in at least 2 degrees of freedom, in planes generally parallel to the nail to locate the axis of the targeting device with the locking holes. The viewing axis of the targeting device must be precisely located to coincide with the axis of the locking holes.